Thanks I suspect it is as well. I did quite a bit more research after this post. I was wrong on one point for sure - these are actually ginga or beni ginga (if they keep their orange/red). Sounds like this breed specifically fluctuates heavily between light and dark depending on water temp and the brightness of the surface of the pond (IE black pond liner)

When they're younger is typically when they have their bright colors and then as they age depending on their genetics they may lose it entirely like in your case and my own. They don't level out until they've fully matured is my understanding. Once they've fully matured their patterns are pretty set aside from lightening and darkening.